Daniel's mother and stepfather were unanimously convicted of murder on Wednesday after blaming each other for the head injury which ultimately caused his death.

Jurors heard how Daniel was systematically starved under the noses of medical professionals and his teachers at Coventry's Little Heath Primary School.

Eleven of the 12 jurors who found Luczak and Krezolek guilty of murder returned to the court today to see them receive mandatory life terms.

One of the jurors wiped away tears as the judge described the ill-treatment of Daniel during her sentencing remarks.

But Luczak and Krezolek simply started straight ahead and listened to their interpreters in the dock, as the judge told them: "As the trial has progressed, harrowing details of the unimaginable acts of cruelty and brutality inflicted on little Daniel, over many months, have exposed both the torment and despair he must have suffered and your callous disregard for his pain and distress.

"Time and again, knowing exactly what you were doing to him, both of you concealed your conduct from the authorities by a series of deliberate and elaborate lies, designed to put them off the scent and to prevent them discovering Daniel's true plight."

The judge added that a determination to lie and to protect themselves at all costs had been the "hallmark" of the defendants' conduct during their campaign of cruelty.

Daniel, whose body weighed just 1 stone 9 lbs, died on March 3 last year, two days after being attacked by Krezolek and subjected to water torture and salt poisoning.

During the 30-hour period in which Daniel lay dying, Luczak, 27, and Krezolek, 34, chose not to call an ambulance, instead opting to carry on with their normal lives.

Daniel Pelka (Image: PA)

Accepting that Daniel appeared to be a healthy and well cared for little boy when he started school in September 2011, the judge told Luczak and Krezolek: "Over the months that followed, he was subjected by both of you to deliberate, escalating and incomprehensible brutality, which continued right up to his death.

"For reasons which are unfathomable, Daniel became a target for derision, abuse and systematic cruelty, designed to cause him significant mental and physical suffering.

"The scale of his suffering was truly horrific."

Evidence that Daniel had been regularly "imprisoned" for prolonged periods of time in a small unheated box room was also presented to the couple's trial.

The door to the room had been adapted by Krezolek so that Daniel, whose emaciated frame was likened to that of a famine victim, could not escape or even see out of the keyhole.

Referring to forensic evidence found on the door, Mrs Justice Cox went on: "The small hand and finger marks on the inside of that door provided a poignant image of his desperate attempts to escape.

"It is a particularly grave aggravating feature in this case that, before the fatal blows to his head, Daniel was the victim of chronic and systematic starvation.

"Both of you deliberately deprived him of food over a prolonged period of time.

"His starvation was so chronic that his bones ceased to grow."

The medical evidence in the case, the judge said, showed that Daniel's emaciation was regarded by experts as "unprecedented" in Britain.

The judge continued: "They likened his appearance to those who failed to survive concentration camps, and that comparison was not made lightly.

"As the months passed, Daniel increasingly scavenged for food, from other children's lunch boxes, from the playground or from rubbish bins.

"He would have suffered extraordinary hunger, increasing abdominal pain and, ultimately, a feeling of hopelessness. You, Magdelena Luczak, knowing of his hunger, gave specific instructions to his teachers that Daniel was not to eat any more food than the small packed lunch he had with him.

"Both of you constructed a careful and wholly untruthful account that Daniel had a serious eating disorder and learning difficulties, which he may have inherited and for which he was receiving medical treatment.

"This account was deliberately designed to prevent interference by school, medical and welfare personnel, and to perpetuate the brutality being meted out to him."